Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1992-7-28
pubmed:abstractText
We show that osteoclasts bind parathyroid hormone (PTH) in a manner that displays the properties of receptor-dependent hormone binding, that is, saturability, time dependence, temperature dependence, and hormone specificity. Osteoclasts were isolated from the endosteum of 2 to 3 week chick tibiae and maintained in culture for 4-6 days. Bovine PTH-(1-84) was biotinylated with N-hydroxysuccinimidobiotin. Biotinyl-PTH (btPTH, 10(-5)-10(-11) M) was added to the cultured osteoclasts for 2-20 minutes. After rinsing away unbound btPTH, fluorescein isothiocyanate-labeled avidin (FITC-avidin) at a concentration of 66 micrograms/ml was applied. Receptor binding characteristics were assessed: (1) saturation occurred at around 10(-6) M btPTH; (2) competition of excess unlabeled PTH was found, namely, a 10-fold excess abolished fluorescence; (3) specificity was shown by adding other polypeptide hormones (insulin, glucagon, and calcitonin) in 10- to 100-fold excess--no effect on PTH binding was observed; and (4) affinity of btPTH for its binding site was indicated by half-maximal binding approximately equal to 10(-7) M for both osteoclasts and osteoblasts. Biotin (10(-5) M) or FITC-avidin (66 micrograms/ml) alone did not cause fluorescence. The time course of btPTH on the cell exterior was short: at 2 and 5 minutes dots of fluorescence were randomly dispersed over the cell surface, by 10 minutes most of the fluorescence was clustered in one region of the membrane, and by 20 minutes most of the hormone was no longer present on the surface of the cells.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0884-0431
pubmed:author
pubmed:issnType
Print
pubmed:volume
7
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
531-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Specific binding of parathyroid hormone to living osteoclasts.
pubmed:affiliation
Zetachron, Inc., State College, Pennsylvania.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't